We have a Yamaha C7 from which we are currently unable to remove any of the lid hinge pins. We have had the lid off this piano several times over many years. Can't get any of the three pins to budge, even with someone raising and lowering the lid while pliers are on the hinge pin, being struck by a rubber mallet.
As you might imagine, we are curious about what may have caused this condition. And knowing the cause may steer us in the right direction about how to remedy it.But regardless of whether or not we figure out the cause, we have to fix it. What is the best brass to brass lubricant? Also, we have considered trying to drive the pins out with a drift, made of either brass or something softer. Anyone with experience doing this care to weigh in?Thanks,Alan
Allan, were the pins replaced with new ones recently. The last hinge pins I got from Yamaha had "kinks" knocked into them, presumably to prevent them from working their way out. But I think they over did it as they were exceedingly difficult to get in.
Good to know about the pre-kinked replacement pins. But no, these were the same pins that have been in and out many times before.
You need to punch the pin with a drift and a steel hammer. If using pliers and a mallet won't work, you've pretty much run out of options. Last time I had this problem, I had to take some metal sanding paper and make the pin smaller before I could put it back in. Last ditch would be to unscrew the hinges and put in a vise. Good luck.
With the lid closed and the rim protected but a small vise grip on the hinge pin and use a dead blow hammer to hit the pliers . You can try doing the same with a drift . It is pretty difficult to unscrew hinges so you will need a number of people able to support the lid Sounds like the pins are bent or wrong size got banged in
I have driven out numerous stubborn hinge pins with a punch. Just need to watch that the hammer doesn't hit stuff its not supposed to smile 🙂
Peter Grey Piano Doctor
Thanks to all who responded to this thread!
Guess I'd lived a charmed existence up to this point, since I never needed anything heavier and harder than a modest rubber mallet to remove all the lid hinge pins I have had to remove over nearly fifty years. We tried steel hammers, but decided to cease and desist when we got to the three pounder and still none of the three lid hinge pins would budge.
Used a 1/8" nail set to get the pins moving just enough to make it possible to pull them the rest of the way out.
These are the original Yamaha pins, which featured opposing flat spots the long arm right before the 90o bend to the short one. All three pins had some "chewed" up surface just before the bend (inside the hinge). The roughness added about .008" to the diameter of the pins, which apparently was enough to keep the pins from being driven out, despite Big Bertha's best efforts (even in the hands of those younger and stringer than me). We sanded those rough areas down with emery cloth until they were closer to the .185" diameter of the body of the pin and were able to reinsert and readily remove them at will.
We are still flummoxed about what happened to this piano to cause the same game-changing roughness to all three pins in the same place. May never know the answer to that particular mystery, but at least we can declare, like the man said, "Mission Accomplished!"
Alan, if memory serves, the pin go in with the "L" facing the front of the piano. Was this the case on yours? Perhaps, if they went in from the rear, that end of the hinge is slightly closed and thus chewed up the pins.
Very interesting point you raise here, Steven! I was not aware of the engineering feature you mentioned in terms of the directionality of pin insertion.
This was the one removal and replacement of the lid in the life of this piano for which I was not personally present, due to extenuating circumstances. And the pins were in fact inserted with the L portion towards the tail on all three pins. You just might win the prize of a Reward In Heaven!